I will tell you that several years ago I was a US Chairman's Preferred flying this route a lot, and specifically, flying on the last DCA to BOS flight. There were 2 times when I got to the gate 10 to 15 minutes early having already checked in, and US DCA had closed the door stranding me in DCA. I could forgive them for this if they had given me a hotel voucher, but they refused. I was able to write to customer relations and get a US voucher for the cost of the hotel; but as a Chairman's Preferred I felt and still feel they should have been better able to handle the problem on the spot at the gate podium.

I put my money where my mouth is, and broke up with US Airways temporarily moving to a United 1K. I went out to IAD a lot and flew UA as my main carrier on this route for a while, and on balance felt I was treated well as a 1K. At the time, also, the IAD fares were a lot less expensive; which I don't think is really true now in 2015.

As noted I've come back now to US (and also B6) , because lets face it, DCA is a lot more convenient than IAD.

I also really like
http://mobile.usairways.com
under flight status because you can look up the standby and upgrade lists even if you aren't booked on a flight. You can see how full the flights are, etc. This functionality is better than American.

That all being said, the JetBlue Mosaic benefit of waiving change and cancel fees really hits the ball out of the park! I mean you can book with a free same day confirmed on JetBlue anytime the same day even if there is just 1 Y seat left on the flight! You can also cancel your trip, and get the full value back in a credit! I doubt 99% of Executive Platinums on AA know about this JetBlue Mosaic benefit! They don't advertise it well! Alaska and Southwest have similar benefits but they won't help us in BOS DCA!

Also most business travelers are not at all savvy with airlines so I bet you a huge number of them don't know about what this Mosaic benefit really means.

I am hesitant to book flights on AA/US because of their ridiculous $200 change and cancel fees. So I tend to only book with them if I am sure I am going that day! I worry about booking a nonrefundable AA/US ticket, where as on JetBlue, I don't have to worry or be anxious!

Of course there are trade offs that we've discussed so no carrier is perfect, and while I like the AA/US service better (think first class & Wi-Fi and running up to the gate at the last minute) I am still booking a heck of a lot of B6 tickets because of no change fees; or Be Fee Free!

I am not sure if the other airlines know this, or maybe because you would only fly B6 a lot out of BOS or JFK the other majors like AA don't care, and maybe say AA is willing to just write off the lost business of the B6 Mosaic flyers who fly them due to no change fees? After all, they may not want to change their whole fare structure just to accommodate bean town flyers! For those of you in other areas, FYI, B6 is now the llargest carrier at Boston Logan taking up almost all of terminal C and they continue to expand BOS nonstops.